Mental skills are required for individuals to think quickly and make correct decisions. It can be said that mental skills, which play an important role in the acquisition of thinking and questioning skills, are only possible with creative, critical, and other high-level thinking skills. In this regard, the PISA exam, which reveals the mathematics achievement levels of countries, is important. Due to the absence of such an exam in the Turkish Republic of Northern Cyprus (TRNC), the descriptive scanning method, one of the quantitative research methods, was used in order to determine the effects on students' abilities in solving non-routine mathematical problems with the methods applied in the mathematics course. Based on this research conducted to determine the skills of 9th-grade high school students in solving non-routine mathematical problems, the mathematics achievement levels of the schools that accept students with special exams in the TRNC have been revealed.

Mental skills are required for individuals to think quickly and make correct decisions. It can be said that mental skills, which play an important role in the acquisition of thinking and questioning skills, are only possible with creative, critical, and other high-level thinking skills. In this regard, the PISA exam, which reveals the mathematics achievement levels of countries, is important. Due to the absence of such an exam in the Turkish Republic of Northern Cyprus (TRNC), the descriptive scanning method, one of the quantitative research methods, was used in order to determine the effects on students' abilities in solving non-routine mathematical problems with the methods applied in the mathematics course. Based on this research conducted to determine the skills of 9th-grade high school students in solving non-routine mathematical problems, the mathematics achievement levels of the schools that accept students with special exams in the TRNC have been revealed.